Glucose Gel for Marathoners

Marathon runners need to replenish the fuel they burn during the race.

The human body is able to store approximately two hours' worth of fuel for high endurance events. Marathon runners ingest glucose gel to replenish used stores during races. The benefits of ingesting glucose gel can last up to 20 minutes.

Use

Glycogen, a form of sugar stored in the muscles, is the body's primary fuel source. If you use up glycogen, the body turns to glucose (blood sugar) to continue functioning.

Replenishment

When you ingest it, glucose is quickly absorbed in the intestinal tract and the body is able to use it for fuel. This rapid absorption allows endurance athletes, such as marathon runners, to preserve their stored glycogen. For optimum effect, you should consume gels every 30 to 40 minutes during activity.

Composition

Most commercially available gels are not pure glucose. While some gels are made up of the same chemical composition of blood sugar, designed for diabetics, most are actually energy gels that are composed of sucrose, fructose and electrolytes, which are designed to be of more benefit to endurance athletes than pure glucose. Energy gels rapidly convert to glucose when ingested.

Side Effects

Side effects of ingesting pure glucose gels can include nausea, possible vomiting, cramping and mild diarrhea.

References

• Queensland Ambulance Service: Glucose Gel
• Washington Running Report: Energy Gels
• Nutrition Success: Marathon Nutrition Guide

Resources

• The Sport Journal: Glycogen Replenishment After Exhaustive Exercise